Method for making drill-chuck jaw with hard-metal inserts

ABSTRACT

A drill-chuck jaw is made by first forming an elongated metal body with a toothed back face and a planar front face and thereafter laser-welding an insert to the body on the face. After machining the body but before laser-welding the inserts to it, the body is heat-treated and surface hardened. After the heat-treating and surface-hardening step and before the laser-welding step, the body in tampered.

FIELD OF THE INVENTION

[0001] The present invention relates to drill-chuck jaw. Moreparticularly this invention concern method making such a jaw equippedwith one or more hard-metal inserts.

BACKGROUND OF THE INVENTION

[0002] A standard drill chuck has a body centered on and rotatable aboutan axis and formed with a plurality of axially extending angled guidesangularly spaced about the axis. Respective jaws in these guides can bemoved between a forward holding position in which they grip a workpieceand a rear releasing position. Teeth on back edges of the jaws mesh witha threaded ring that is rotated relative to the chuck body to advanceand retract the jaws. Alternately the guides are formed in a sleeve thatrotates relative to the chuck body and the teeth on the jaws mesh with ascrewthread on the body for similar action.

[0003] Even though the jaws are made of steel, they are typically usedto grip tools of similar hardness. Thus it is known to provide specialhard-metal, e.g. carbide, inserts in the gripping faces of the jaw toreduce wear of the jaws and thereby prolong the life of the drill orlathe carrying the chuck.

[0004] Such inserts must be mounted very, very solidly on the chuckjaws. Once installed they must be able to withstand considerable lateralforces as the chuck applies torque to the tool, and they must hold evenwhen the entire tool gets fairly hot as in common machining.

[0005] In commonly owned U.S. Pat. No. 6,427,555 we disclose such ajaw-making method comprising the steps of forming an elongated metalbody with a toothed back face and a front face, machining alongitudinally extending groove having sides and a floor in the frontface, forming on each of the groove sides a pair of inwardly projectingand longitudinally spaced bumps with the bumps on one of the groovesides transversely aligned with the bumps on the other of the groovesides, fitting into the groove between the pairs of retaining bumps ahard-metal insert, and bonding the insert to the body in the groove.

[0006] While this procedure produces a very strong jaw with a verysolidly mounted insert, it is quite difficult and complex. Machining thegroove and providing the holding bumps adds two steps to themanufacturing process. Furthermore once the insert is thus mounted it isstandard to subject the entire jaw, with insert, to variousheat-treating steps that in fact reduce the hardness of the insertand/or jaw. Furthermore the presence of solder or adhesive between theinsert and the body face it is mounted to, normally the floor of thegroove, requires that the insert be machined after attachment of theinserts to guarantee perfect positioning of the insert faces.

OBJECTS OF THE INVENTION

[0007] It is therefore an object of the present invention to provide animproved method of making a drill-chuck jaw.

[0008] Another object is the provision of such an improved method ofmaking a drill-chuck jaw which overcomes the above-given disadvantages,that is which is relatively simple and which produces a very strong andhard jaw.

SUMMARY OF THE INVENTION

[0009] According to the invention a drill-chuck jaw is made by firstforming an elongated metal body with a toothed back face and a planarfront face and thereafter laser-welding an insert to the body on theface. More particularly, after machining the body but beforelaser-welding the inserts to it, the body is heat-treated and surfacehardened.

[0010] Thus with this method it is normally only necessary to form asimple planar face on the jaw. This is a relatively easy procedurecompleted quickly and very accurately by milling. By not using solder oran adhesive between the insert and the face, positioning will be perfectso that no subsequent machining of the jaw will be necessary. What ismore the laser welding operation is so accurate and quick that itintroduces no meaningful stresses into the workpiece, so once the insertis lager-welded in place, the workpiece is finished.

[0011] According to the invention, after the heat-treating andsurface-hardening step and before the laser-welding step, the body istampered. Thus this step is also completed before the insert or insertsare laser-welded in place.

[0012] In accordance with another feature of the invention, before theheat-treating and surface-hardening step a longitudinally extendingcentering formation in formed on the face. Thereafter but before thelaser-welding step, the insert is fitted to the formation.

BRIEF DESCRIPTION OF THE DRAWING

[0013] The above and other objects, features, and advantages will becomemore readily apparent from the following description, reference beingmade to the accompanying drawing in which:

[0014]FIGS. 1 and 2 are side views of a drill-chuck jaw according to theinvention;

[0015]FIG. 3 is a section taken along line III-III of FIG. 2;

[0016]FIG. 4 is a side view of another jaw;

[0017]FIG. 5 is a section taken along line V-V of FIG. 4;

[0018]FIG. 6 is a side view of yet another jaw;

[0019]FIG. 7 is a section taken along line VII-VIl of FIG. 5;

[0020]FIGS. 8 and 9 are views like FIG. 7 of further chucks inaccordance with the invention; and

[0021]FIG. 10 is a block diagram illustrating the method of thisinvention.

SPECIFIC DESCRIPTION

[0022] As seen in FIG. 1 through 3 and 10, a drill-chuck jaw 1 accordingto the invention is made by first machining a cylindrical steel body orpin so that one side has at one end a row of teeth 2 extending parallelto a center axis 4 of the pin, and then machining at the opposite end,and here on the opposite side, a planar face 3 extending at a smallacute angle across the axis 4. Then the workpiece is heat treated toreduce internal stresses. Subsequently it is surface hardened.

[0023] Thereafter hard-metal inserts 5 are positioned on the face 3 andsecured thereto by laser-welds 8. Thus the various treatments are allcompleted before these inserts 5 are installed. The laser-welding doesnot create any significant stresses in the steel of the jaw 1, so thatonce the inserts 5 are mounted, the jaw is complete.

[0024]FIGS. 4 and 5 show how the face 3 is formed with a centrallongitudinally extending rib 6 that is fitted to a groove 7 in the jaw 5a. The interfit of the formations 6 and 7 ensures perfect positionign ofthe inserts 5, making welding them easier.

[0025] In FIGS. 6 and 7 the face 3 is formed with a square-section rib 6b and the jaw 5 b has a square-section groove 7 b complementary to it.FIG. 8 shows a semicircular-section rib 6 c and a complementary groove 7c.

[0026] In FIG. 9 the face is formed with a square-section groove 6 dinto which the entire insert 5 is set.

I claim:
 1. A method of making a drill-chuck jaw comprising the steps of sequentially; forming an elongated metal body with a toothed back face and a planar front face; and laser-welding an insert to the body on the face.
 2. A method of making a drill-chuck jaw comprising the steps of sequentially: forming an elongated metal body with a toothed back face and a planar front face; heat-treating and surface hardening the body; and laser-welding an insert to the body on the face.
 3. The jaw-making method defined in claim 2, further comprising after the heat-treating and surface-hardening step and before the laser-welding step the step of tampering the body.
 4. The jaw-making method defined in claim 2, further comprising before the heat-treating and surface-hardening step the steps of forming a longitudinally extending centering formation on the face, and thereafter but before the laser-welding step; fitting the insert to the formation. 